Special sense

Question 1

location of general sense organs

Answer 1

• exteroceptors (cutaneous)
• visceroceptors
• proprioceptors (joints, muscles, tendons)

Question 2

where are osmoreceptors

Answer 2

hypothalamus → detect changes in osmolarity

Question 3

olfactory R

Answer 3

detect odorant chemical in solutions

• cilia in roof of nasal cavity (olfactory epithelium)
• olfactory bulb/N needs to be covered in mucous to be working
• olfactory centres in temporal lobe → interpretation, integration, memory (limbic system)
• also links to taste

Question 4

7 qualities pf smell

Answer 4

associated with memory

• pepperminty
• musky
• floral
• ethereal (triggers memory)
• pungent
• putrid
• camphoraceous (moth balls)

Question 5

taste (gustation)

Answer 5

• salty (rostral lateral) → Na enter cells
• sour (caudal lateral) → senses HCl, H+ enter cells
• bitter (back) → sense quinine
• sweet (tip) → sense sucrose
• umami → ‘meaty/savoury taste’ senses MSG

Question 6

papillae

Answer 6

• each pap has 1-100 taste buds
• each bud has 50-150 taste cells (are not neurons)
• form synapses gustatory afferent axons → tastants dissolved in saliva binds to R

Question 7

taste

Answer 7

ANT 2/3 → facial N
POS 1/3 → glossopharyngeal N
- N → medulla → thalamus → taste center in parietal lobe (limbic system to develop memories)

Question 8

structures of ear

Answer 8

• pinna, tragus (ear lobe)
• ex acoustic meatus → leads to tympanic membrane
• mid ear bone → malleolus, incus, stapes
• eustachian tube → mid ear to nasopharynx (equalises pressure b/w ex and mid ear
• oval window
• inner ear

Question 9

cochlear

Answer 9

contains organ of corti

- consist of supporting cells and hair cells

Question 10

how does sound waves vibrate hair cells

Answer 10

sound waves → move endolymph → deform hair cells → open/close channels → AP → cochlear branch of vestibulocochlear N

Question 11

maintaining static equilibrium

Answer 11

by vestibule

- detects head position in relation to gravity/acceleration when motionless

Question 12

dynamic equilibrium

Answer 12

semicircular canal

- detection of movement of endolymph in canal

Question 13

how is hearing impairment established

Answer 13

• poor air conduction (form build up of air cerumen)

- presbycusis → hearing loss associated with ageing (hair cell damage/atrophy)

Question 14

meniere’s disease

Answer 14

excessive endolymph accumulation → increase pressure that disrupts balance and hearing

Question 15

fibrous layer of vision

Answer 15

• sclera (white covering eye)

- cornea (outside layer continuous with sclera)

Question 16

vascular layer

Answer 16

• choroid (BS to eye)
• ciliary body (continuous with choroid, and prod aq/virtreous humour)
• iris (circular muscles controlling size of pupil)

Question 17

inner layer

Answer 17

retina

• contains optic disc (blind spot → optic N leaves retina)
• fovea → high conc of cones

optic N (no sensory cells are at entry of optic N)

retinal BV

Question 18

3 types of optic neurons

Answer 18

photoR (rods/cones) → bipolar neurons → ganglion neurons → optic N → occipital lobe

Question 19

ratio of rods and cones

Answer 19

high rods (B&W) : low cones (colour)

Question 20

what prevents eyeball from collapsing

Answer 20

vitreous humour
- fills POS cavity

Aq humour

• fills ANT cavity
• prod. by ciliary body
• drained by canal of schlemm

Question 21

glaucoma

Answer 21

inability to drain aq humour

- damages lens structures

Question 22

physiology of vision

Answer 22

• processes to focus light (IF

Question 23

if >6m away

Answer 23

accommodation, constriction, convergence not required

Question 24

presbyopia

Answer 24

ageing → lose elasticity → inability to bulge and accommodate for near vision

Question 25

myopia

Answer 25

short-sighted

- image focused in front of fovea

Question 26

hyperopia

Answer 26

long-sighted

- image focused behind fovea

Question 27

astigmatism

Answer 27

irregular curvature of cornea (different points of focus on retina)

Question 28

cataracts

Answer 28

cloudy area within lens due to age-related degeneration

Question 29

retinal detachment (retinoschisis)

Answer 29

fluid accumulation → seperates retina from underlying tissues (AMD)